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Diffstat (limited to 'lib/hipe/test/basic_SUITE_data/basic_bugs_beam.erl')
-rw-r--r-- | lib/hipe/test/basic_SUITE_data/basic_bugs_beam.erl | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/lib/hipe/test/basic_SUITE_data/basic_bugs_beam.erl b/lib/hipe/test/basic_SUITE_data/basic_bugs_beam.erl new file mode 100644 index 0000000000..964b0f423a --- /dev/null +++ b/lib/hipe/test/basic_SUITE_data/basic_bugs_beam.erl @@ -0,0 +1,138 @@ +%%% -*- erlang-indent-level: 2 -*- +%%%------------------------------------------------------------------- +%%% Author: Kostis Sagonas +%%% +%%% Contains code examples that exhibited bugs in the BEAM compiler. +%%%------------------------------------------------------------------- +-module(basic_bugs_beam). + +-export([test/0]). + +%% the following is needed for the test_weird_message +-export([loop/1]). +%% the following are needed for the test_catch_bug +-behaviour(gen_server). +-export([start_link/1]). +-export([init/1, handle_call/3, handle_cast/2, handle_info/2, + terminate/2, code_change/3]). + +test() -> + ok = test_fp_basic_blocks(), + ok = test_weird_message(), + ok = test_catch_bug(), + ok. + +%%-------------------------------------------------------------------- +%% Test which shows that BEAM's splitting of basic blocks should take +%% into account that arithmetic operations implemented as BIFs can +%% also cause exceptions and thus calls to BIFs should end basic blocks. +%% +%% Investigated and fixed in the beginning of April 2004. +%%-------------------------------------------------------------------- + +test_fp_basic_blocks() -> + ok = t1(), + ok = t2(). + +t1() -> + X = (catch bad_arith1(2.0, 1.7)), + case X of + {'EXIT', {badarith, _}} -> + ok; + _ -> + error + end. + +bad_arith1(X, Y) when is_float(X) -> + X1 = X * 1.7e+308, + X2 = X1 + 1.0, + Y1 = Y * 2, + {X2, Y1}. + +%% Similarly, it is not kosher to have anything that can fail inside +%% the fp block since it will throw the exception before the fp +%% exception and we will get the same problems. + +t2() -> + case catch bad_arith2(2.0, []) of + {'EXIT', {badarith, _}} -> + ok; + _ -> + error + end. + +bad_arith2(X, Y) when is_float(X) -> + X1 = X * 1.7e+308, + Y1 = element(1, Y), + {X1 + 1.0, Y1}. + +%%-------------------------------------------------------------------- +%% Sending 'test' to this process should return 'ok'. But: +%% +%% 1> MOD:test(). +%% Weird: received true +%% timeout +%% +%% Surprisingly, the message has been bound to the value of 'ena' +%% in the record! The problem was visible in the .S file. +%%-------------------------------------------------------------------- + +-record(state, {ena = true}). + +test_weird_message() -> + P = spawn_link(?MODULE, loop, [#state{}]), + P ! {msg, self()}, + receive + What -> What + after 42 -> timeout + end. + +loop(S) -> + receive + _ when S#state.ena == false -> + io:format("Weird: ena is false\n"); + % loop(S); + {msg, Pid} -> + Pid ! ok; + % loop(S); + Other -> + io:format("Weird: received ~p\n", [Other]) + % loop(S) + end. + +%%-------------------------------------------------------------------- +%% This was posted on the Erlang mailing list as a question: +%% +%% Given the module below and the function call +%% "catch_bug:start_link(foo)." +%% from the Erlang shell, why does Erlang crash with "Catch not found"? +%% +%% The BEAM compiler was generating wrong code for this case; +%% this was fixed in R9C-0. Native code generation was OK. +%%-------------------------------------------------------------------- + +test_catch_bug() -> + ignore = start_link(foo), + ok. + +start_link(Param) -> + gen_server:start_link(?MODULE, Param, []). + +init(Param) -> + process_flag(trap_exit, true), + (catch begin + dummy(Param), + (catch exit(bar)) + end + ), + ignore. + +dummy(_) -> ok. + +%% gen_server callbacks below +handle_call(_Call, _From, State) -> {noreply, State}. +handle_cast(_Msg, State) -> {noreply, State}. +handle_info(_Msg, State) -> {noreply, State}. +terminate(_Reason, _State) -> ok. +code_change(_OldVsn, State, _Extra) -> {ok, State}. + |